1. Field of the Invention
This invention relates to novel copolymeric products containing starch and polyamideamine components, a method for the preparation thereof and a method for using the same. More specifically, the invention is directed to starch graft copolymers of starches and polyamideamines, their preparation and the use of these graft copolymers as wet-strength additives for paper.
2. Brief Description of the Prior Art
The use of and synthesis of cationic thermosetting resins formed by the reaction of a polyalkylene polyamine with dibasic acid reagent and the subsequent reaction of the intermediate product with epichlorohydrin or a similar chain extending agent is well known in the art. In certain instances, additional reactants are utilized in the preparation of the intermediate, such for example, as a lactone or alkyl acrylate or methacrylate ester or a lactam. The production of such resins in relatively high yields with good reaction efficiency is taught in U.S. Pat. Nos. 2,926,116; 2,926,154; 3,058,873; 3,159,612; 3,227,671; 3,250,664; 3,442,754 and 3,647,763. The resulting resins are particularly useful as wet strength additives in the paper making process; however, due to their relatively expensive production costs, their use is not widespread. Attempts to dilute the polyamideamine resins, such as by blending with starch, have heretofore proved fruitless due to the subsequent reduction in wet strength performance of the blended material.
There is thus a need in the art for a polyamideamine containing product which is both economically feasible and which exhibits the superior wet-strength performance of the pure chain-extended polyamideamine resin when employed in the paper-making process.